Landslides Triggered by Pacific Northwest Storms
WARNING: Provisional Data, Subject to Revision
| Location | County | State | Lat. (deg. North) | Long. (deg. West) | Landslide type | Height, m | Width, m | Depth, m | Slope Angle, degrees | Geologic Materials | Damage | Continuing Hazards | Continuing Activity |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sunrise Beach, Gig Harbor Penninsula | Pierce | WA | 47.345 | 122.557 | Earth slide | 25 | 20 | 0.5-2 m | 46 | Silt and fine sand | Pushed house off foundation | Neighboring slopes could fail | Seepage from adjacent hillside north of scar, and from north edge of scar |
| Cromwell Drive SW, Gig Harbor Penninsula | Pierce | WA | 47.272 | 122.606 | Debris flow | 30 | 6 | 0.5 | 25 | Sand and gravel | Temporarily blocked road | ||
| Cromwell Drive SW, Gig Harbor Penninsula | Pierce | WA | 47.271 | 122.611 | Earth slide and rapid earth flow | 30 | 50 | 0.5-10 | 40 | Sand and gravel | Temporarily blocked road | Potential for additonal earth flow and deep seated movement could damage property above slide | Small earth flows, seepage from toe of slide, which overlies a bed of silty clay |
| State Highway 34, 5 miles northeast of Alsea | Benton | OR | 44.434 | 123.535 | Debris flow | 20-30 | Sand and gravel | Destroyed house, temporarily blocked road & culvert | |||||
| State Highway 34, west of Alsea | Lincoln | OR | 44.392 | 123.834 | Debris flow | 15 | 14 | 0.5-5 | Clayey sand, weathered rock | Temporarily blocked road | Potential for additonal debris flow | Seepage from scar | |
| State Highway 229, 13 miles north of Siletz | Lincoln | OR | 44.839 | 123.974 | Earth slide | 15(?) | 50-60 | 2-10 | Artificial fill, weathered claystone | Destroyed 15-20 m of southbound lane | |||
| U.S. Highway 101, about 1 mile south of Beaver | Tillamook | OR | 45.266 | 123.848 | Rock fall and rock slide | 25 | 20-25 | 0.5-2 | 65 | Weathered volcanic breccia | Temoprarily blocked both lanes of highway | Overhanging ledge has potential for future rock fall | |
| Blain Road bypass, east of Beaver | Tillamook | OR | 45.282 | 123.812 | Rock fall and rock slide | 40-45 | 90 | 0.5-2.5 | colluvium derived from weathered volcanics (?) | Temporarily blocked road | Potential for future rock fall and debris flow | ||
| Nestucca River basin, 14 miles east of Beaver | Tillamook | OR | 45.242 | 123.605 | Debris flow | 3-10 | 1-2 | Gravel-, cobble-, and boulder-sized rocks in a sandy matrix | Temporarily blocked road | Potenitial for future debris flow? | |||
| Nestucca River basin, 14 miles east of Beaver | Tillamook | OR | 45.24 | 123.603 | Debris flow | 5-6 | 0.5-2 | Fine clayey sand | Temporarily blocked road, 2nd pulse nearly struck maintenance equipment | Potenitial for future debris flow? | |||
| Nestucca River basin, 14 miles north of Beaver | Tillamook | OR | 45.24 | 123.603 | Earth slides | 10-15 | 3-10 | 0.5-1.5 | Sandy clay derived from weathered shale | Temporarily blocked road | |||
| Bible Creek Road | Tillamook | OR | 45.223 | 123.568 | Earth slide | 4-5 | 14 | 2-3 | 38 | Clayey sand derived from weathered gabbro or diorite | Temporarily blocked road | ||
| Bible Creek Road | Tillamook | OR | 45.223 | 123.567 | Earth slide and debris flow | 25 | 15 | 0.5-2 | 40-45 | Clayey sand derived from weathered gabbro or diorite | Temporarily blocked road | Potenitial for future debris flow |
Information concerning the accuracy and appropriate uses of these data may be obtained from:
| Alan Chleborad | Rex Baum U.S. Geological Survey Geologic Hazards Team Box 25036, M.S. 966 Denver, CO 80225 baum@usgs.gov |
